New research suggests that olive oil could reduce your risk of death, including from heart disease, stroke, cancer and dementia.
Although the link between olive oil and reduced risk of heart disease is well known, the researchers wanted to find out if it is linked to a reduced risk of death overall.
The study, published in the Journal of the American College of Cardiology, analysed the diet of around 90,000 men and women over a 28-year period. None of them had heart or circulatory disease or cancer at the outset. Every four years they were asked how often they ate specific foods.
Researchers found those who consumed the most olive oil (more than half a tablespoon a day) were less likely to die from any cause, including heart disease or stroke, cancer, lung disease and neurodegenerative disease (such as Alzheimer’s disease or vascular dementia).
After adjusting for other factors, the people who ate the most olive oil had a 19 per cent lower risk of dying from cardiovascular causes such as heart disease or stroke, compared with the people who ate the least olive oil. The biggest effect was seen in neurodegenerative disease deaths (29 per cent lower risk in people who ate most olive oil). For respiratory disease the risk was 18 per cent lower and for cancer it was 17 per cent lower.
The study also found substituting 10 grams a day (just over a tablespoon) of fats such as margarine, butter, mayonnaise and dairy fat with the equivalent amount of olive oil was also associated with a lower risk of death.
Although this kind of study can’t prove cause and effect, the researchers said there are potential reasons why olive oil might reduce death risk from such a range of diseases. Olive oil contains monounsaturated fat and specific plant compounds, which may have a positive effect on blood pressure and cholesterol levels, as well as having anti-inflammatory and anti-carcinogenic properties, and encouraging healthy gut bacteria. The study’s lead author said: “Our findings support current dietary recommendations to increase the intake of olive oil and other unsaturated vegetable oils.”
How good was the research?
A major advantage of the study was the large number of people taking part over a long period of time. They were all nurses and other health professionals in the United States, so their lifestyles might not be representative of the population as a whole.
How good was the news coverage?
The Times carried two articles about the research, a news story and a feature which included an interview with the study author. Both were relatively accurate, but didn’t explain that the researchers had adjusted the findings to take other factors into account that could influence the results. This means the differences seen are more likely to be related to olive oil (and not, for example, that the olive oil eaters also ate more salads) although with observational studies like this, we can never be certain.
The Mail article did explain that the results had been adjusted to take other factors into account. Less accurately, the article says: “Their study is the latest to tout the health benefits of the Mediterranean diet, which A-list celebrities like actress Penelope Cruz have raved about for years.” Although olive oil is a component of the Mediterranean diet, olive oil alone doesn’t make it Mediterranean. The Mediterranean diet is a whole way of eating that includes lots of vegetables and fruit, grains, beans and lentils, nuts and seeds, and small amounts of meat and dairy.
The BHF verdict
We know from previous studies olive oil may have a range of health benefits, and this study supports existing recommendations for heart and circulatory health. Replacing saturated fats in your diet (like butter, lard, and ghee) with unsaturated fats like olive, sunflower or vegetable oil can help to lower cholesterol levels. Olive oil is also a well-known part of the Mediterranean diet, which is a dietary pattern associated with better heart and circulatory health.
This study is helpful to broaden our understanding of how olive oil may reduce the risk of death from other conditions, not just heart disease. However more evidence is required to say there is a direct link between the consumption of olive oil and lowered risk of dying.
The study doesn’t tell us whether olive oil is healthier than other plant oils like sunflower or rapeseed.
As part of a healthy, balanced diet, switching from butter, ghee or lard to unsaturated fats like olive oil is an easy change whether you use it in salad dressings, to drizzle it on bread instead of using butter, or for frying and roasting.
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